Preserve DesignPreserve Design

1.Acadia (ME)2.Arches (UT) 3.Badlands (SD) 4.Biscayne (FL) 5.Bryce Canyon (UT) 6.Canyonlands (UT)7.Capitol Reef (UT) 8.Colonial Williamsburg (VA 9.Ellis Island (NY) 10.Everglades (FL) 11.Glacier (MT) 12.Glen Canyon-Lake Powell (AZ) 13.Grand Canyon (AZ)14.Grand Teton (WY) 15.Great Smoky Mountains(TN)

16.Hawaii Volcanoes (HI) 17.Kings Canyon (CA) 18.Mount Rainier (WA)19.Mount Rushmore (SD)20.Olympic (WA) 21.Rocky Mountain (CO) 22.Sequoia (CA) 23.Shenandoah (VA) 24.Statue of Liberty (NY) 25.Waterton Lakes (CAN) 26.Yellowstone (WY) 27.Yosemite (CA) 28.Zion (UT)

% Saturation% Saturation

Curve through New Guinea and nearby Kei islands

Closed circles - more distant islands

% of expected # of species if lying on saturation curve

Yellowstone GrizzliesYellowstone Grizzlies

• Needs 50-90 Needs 50-90 for viable for viable populationpopulation

• Takes 1000-Takes 1000-13500 km13500 km22

Extinction parameter (Extinction parameter (kk))

• Land bridge Land bridge islands in the West islands in the West IndiesIndies

• Extinction vs. Extinction vs. island sizeisland size

• Prediction for Prediction for Barro Colorado Barro Colorado island: 16-17island: 16-17

dS/dt = kS2

k for Birds on Land Bridge Islands in the West Indies

Park # Mammal species % lost

Bryce Canyon 5 36

Mount Rainier 7 32

Rocky Mountain 2 31

Yosemite 4 25

Grand Teton/Yellowstone 1 4

Lassen Volcanic 6 43

Kootenay/Banff/Jasper/Yoho 0 0

Mammal species lost since Park establishment

Reasons for Large SizeReasons for Large Size• Larger S than a single smaller reserveLarger S than a single smaller reserve

• Slower rate of relaxationSlower rate of relaxation

• Some habitats can only exist on larger fragmentsSome habitats can only exist on larger fragments

• Small perimeter compared with area - less edge effectSmall perimeter compared with area - less edge effect

• Required to support larger predators, or species that rely on Required to support larger predators, or species that rely on seasonal or patchy resourcesseasonal or patchy resources

• Withstand variations in nutrient flow or pollution insultWithstand variations in nutrient flow or pollution insult

• Less sensitive to disturbance - maintains high species richnessLess sensitive to disturbance - maintains high species richness

• Ensures that succession will lead to a range of habitatsEnsures that succession will lead to a range of habitats

• Support poor dispersersSupport poor dispersers

• Allows predators to move between unoccupied patches for preyAllows predators to move between unoccupied patches for prey

Reasons for Small SizeReasons for Small Size• More combinations - time of arrivalMore combinations - time of arrival

• Large edge effect may accommodate more species Large edge effect may accommodate more species that prefer edges.that prefer edges.

• May be more prone to disturbance May be more prone to disturbance

• The possibilities of landfall for a migrant may be The possibilities of landfall for a migrant may be greater on a spread of small islands.greater on a spread of small islands.

• If different species go extinct on different islands, If different species go extinct on different islands, smaller islands will between them hold a large smaller islands will between them hold a large number of species.number of species.

Small preservesSmall preserves• Simberloff and Abele Simberloff and Abele -series of small -series of small

preserves may be better:preserves may be better:

– entire group less susceptible to large entire group less susceptible to large catastrophecatastrophe

– may allow survival of competitorsmay allow survival of competitors

– might be better for preserving a range of rare might be better for preserving a range of rare and scattered habitats.and scattered habitats.

Hawaiian IslandsHawaiian Islands(Quinn and Harrison (1988)(Quinn and Harrison (1988)

0

10

20

30

40

50

60

70

80

0 5000 10000 15000 20000

Small first Large first

Area (square km)

# of Avian Species

For Single Species For Single Species PreservationPreservation

• Large reserves Large reserves have several advantages:have several advantages:

Fewer chance extinctions because of large population Fewer chance extinctions because of large population sizes.sizes.

Less likely to be destroyed by major environmental Less likely to be destroyed by major environmental events like floods or fire.events like floods or fire.

Will support larger populations less prone to a loss of Will support larger populations less prone to a loss of

genetic variabilitygenetic variability..

Items to considerItems to consider

• Habitat heterogeneityHabitat heterogeneity

• Edge effect (linear vs. spherical)Edge effect (linear vs. spherical)

• Immigration possibilities (proximity of Immigration possibilities (proximity of other reserves)other reserves)

• CorridorsCorridors

• Inbreeding in small populationsInbreeding in small populations

Design of PreservesDesign of PreservesExtinctionExtinction

lowerlower

higherhigher

Common algorithms usedCommon algorithms used

• ““Greedy” or richness based Greedy” or richness based – Initially adds the site containing the most Initially adds the site containing the most

speciesspecies– Continues moving down site listContinues moving down site list

• Rarity basedRarity based– Chooses sites in order of the rarity of the Chooses sites in order of the rarity of the

species they containspecies they contain– Good at getting minimum number of sites Good at getting minimum number of sites

representing all species in given localerepresenting all species in given locale